This paper assesses the feasibility of direct disposal of loaded dual-purpose canisters (DPCs) from a criticality standpoint by evaluating attributes that could be credited to justify that the DPCs remain subcritical over a repository performance period. This study investigates the uncredited criticality margin associated with actual fuel loading compared with the regulatory licensing design basis limits and evaluates the percentage of DPCs that remain subcritical solely based on the uncredited criticality margin.
The Radioactive Waste Management Directorate (RWMD) is responsible for implementing
geological disposal of the UK’s higher-activity radioactive wastes. RWMD’s research into
geological disposal considers safety during waste transport to a disposal facility, during
waste disposal operations, and once the facility has been closed. The wastes for disposal
comprise a wide range of materials and include some fissile radionuclides. The presence of
fissile materials requires an assessment of the potential for criticality.
Criticality Safety and Shielding Evaluations of the Codisposal Canister in the Five-Pack DHLW Waste Package
The objective of this analysis is to characterize a codisposal canister containing MIT or ORR fuel in the Five-Pack Defense High-Level Waste (5-DHLW) Waste Package (WP) to demonstrate concept viability related to use in the Mined Geologic Disposal System (MGDS) environment for the postclosure time frame. The purpose of this analysis is to investigate the disposal criticality and shielding issues for the DHLW WP and establish DHLW WP and codisposal canister compatibility with the MGDS, and to provide criticality and shielding evaluations for the preliminary DHLW WP design.
The purpose of this calculation is to perform degraded mode criticality evaluations of plutonium disposed in a ceramic waste form and emplaced in a Monitored Geologic Repository (MGR). A 5 Defense High-Level Waste (DHLW) Canister Waste Package (WP) design, incorporating the can-in-canister concept for plutonium immobilization is considered for this calculation. Each HLW glass pour canister contains 7 tubes. Each tube contains 4 cans, with 20 ceramic disks (immobilized plutonium) in each.
This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development (WPD) department with the objective of providing a comprehensive, conservative estimate of the consequences of the criticality which could possibly occur as the result of commercial spent nuclear fuel emplaced in the underground repository at Yucca Mountain. The consequences of criticality are measured principally in terms of the resulting changes in radionuclide inventory as a function of the power level and duration of the criticality.
3rd WP Probabilistic Criticality Analysis: Methodology for Basket Degradation with Application to Commercial SNF
This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development (WPD) department to describe the latest version of the probabilistic criticality analysis methodology and its application to the entire commercial waste stream of commercial pressurized water reactor (PWR) spent nuclear fuel (SNF) expected to be emplaced in the repository. The purpose of this particular application is to evaluate the 21 assembly PWR absorber plate waste package (WP) with respect to degraded mode criticality performance.
This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development Department (WPDD) to determine the viability of the UCF waste package concept with respect to criticality regulatory requirements in compliance with the goals of the Waste Package Implementation Plan5·1 for conceptual design. These design calculations are performed in sufficient detail to provide a comprehensive comparison base with other design alternatives.
The Monitored Geologic Repository Waste Package Operations of the Civilian Radioactive Waste Management System Management & Operating Contractor (CRWMS M&O) performed calculations to provide input for disposal of spent nuclear fuel (SNF) from the Training, Research, Isotopes, General Atomics (TRIGA) reactor (Ref. 1). The TRIGA SNF has been considered for disposal at the potential Yucca Mountain site.
Evaluation of Codisposal Viability for Aluminum-Clad DOE-Owned Spent Fuel: Phase I Intact Codisposal Canister
This evaluation is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development Department (WPDD) to provide analyses of disposal of aluminum (AI)-based Department of Energy-owned research reactor spent nuclear fuel (DOE-SNF) in a codisposal waste package with five canisters of high-level waste (HLW). The analysis was performed in sufficient detail to establish the technical viability of the Al-based DOE-SNF codisposal canister option.